[iLearner]

new weaponid, ammo;
for (new i = 0; i < 12; i++)
{

GetPlayerWeaponData(playerid, i, weaponid, ammo);
if(weaponid > WEAPON_ID_HERE || weaponid > WEAPON_ID_HERE ....)
{
SetPlayerAmmo(playerid, weaponid, ammo+VALUE_HERE);
}

}